Octagon 40 ECO: Economic to buy - simple and effective to use Temperature is measured using the purpose made liquid in glass thermometer that is supplied with the incubator and the incubation temperature adjusted to suit the eggs being incubated as listed in the user instructions. A flashing indicator shows that the incubation temperature is being controlled steadily. Humidity and ventilation. Air is circulated by long life computer fans which, coupled with the unique grilles with optimised air diffusers, means extremely even air temperature throughout the egg chamber. Fresh air is controlled with a vent slider and humidity is provided by water in reservoirs in the base.